What is the purpose of the skid plate?
 

My 2.7t does not have a skit plate.

and my 2.8's broke. Is the only purpose of this to protect the oil pan or does it also help with protecting parts from getting wet?

my 2.7 does not have it and the secondary air pump is making a jet like sound. maybe its because its gotten wet?

its main purpose is to smooth airflow underneath the car giving you better gas milage...

Uh...to skid over road obstructions?
OK, it's not a ski plate, it's a plastic belly pan and it's to protect the bottom of the engine compartment and control airflow. It minimizes splashes on the serp belt and keeps things cleaner. It also serves to catch things you drop when working on the engine..:<)

SAI Pump making jet sound is more likely because of an air leak.

What skid plate? Not a factory item.

LOL Ain't that the truth. Last time I had to remove the plastic belly pan it was to get a tool I dropped, which of course created much more work than the originally intended project.

As cited it's not a skid pad, which is typically rugged metallic and for mechanical protection on off-road vehicles.

bzzzzt - nope, sorry.

Since I've had my 2.7t since new, I was around when Audi retrofitted the "skid plate", which, as mentioned, is nothing of the kind, simply a plastic part that fills in the gap behind the bumper cover. Originally, '01 and before (maybe later models) had NOTHING to fill that gap. It was presented to current owners as a safety retrofit. It seems people would pull into parking spots with those pesky concrete logs, overrun the concrete and when trying to back off, would pull the entire bumper cover off. There was a growing PR issue with this because the repair was around $2000 if you messed it up good. I did it once and had to jack up the front end to get it to clear the concrete without damage.

Later, other VAG products were designed with them. That's when the oil change shops started refusing service to VW and Audi owners because their employees couldn't put it back on right and were shelling out many dollars for replacements :)

So, yes, the smooth underbody has been proven to aid fuel mileage and keeps things from splashing, BUT the real reason they first appeared on A6's was because of a liability issue.

LQ did not add any plastic thing to fill any gap. They simply installed brackets to lower the fastening point of the front of the plastic belly pan.

There is no skid plate.

Where do you people get this wrong information? LOL.

Wrong
 

probably the same place you get yours, the question is who gets it cheaper.

is only a sound deadening device, nothing else. it won't protect the engine at all in case of bottoming out or objects on the road, (ALLROAD uses one made of carbon fiber and metal for this purpose), which barely does the job anyway.
they been used for a long time since the Audi 80 in the late 80s.
as any other cover on top of the engine, serves no particular purpose other than covering things so things look better than they actually are.
Audi as most other companies have learn to use this things as they conceal oil leaks while under warranty avoiding costly repairs.
4d4 is right on the bumper/cover recall, it just makes it hang lower than the bumper preventing it from getting caught as the car moves backwards.

jet
 

just FYI the air pump in the 2.7 seats up high in the engine close to the firewall.
would be very difficult for anything to splash up there with or with a cover plate at the bottom.
the jet noise means is coming to the end of its days.